As known, a rapid prototyping (RP) technology is developed from the concepts of forming a pyramid by stacking layers, and the main technical feature is to achieve fast formation. A complicated design can be transformed into a three-dimensional physical model automatically and fast without any cutting tools, molds and fixtures. Thus, the development cycle of new products and research and development cost are largely reduced to ensure the time to market for new products and the first-time-right ratio. Accordingly, a complete and convenient product design tool is provided between technicians and non-technicians (e.g. managers and users), and the product competitiveness and the quick reaction capability of enterprises in the market are improved obviously.
Nowadays, the rapid prototyping technology is widely applied to the three-dimensional (3D) printing methods. For example, a binder jetting technology (also known as an inkjet powder printing technology) is one of the 3D printing methods. For example, by combining a precise inkjet printing technology and a precise carrier positioning technology, a three-dimensional physical model can be produced. The producing method begins by first spreading a layer of powder on the carrier and then printing high viscosity liquid binder on part of the powder by using the precise inkjet printing technology, so that the liquid binder and the powder stick together to become solidified. After the above steps are repeatedly done, a three-dimensional physical model is produced by stacking multiple layers.
FIG. 1A is a schematic perspective view illustrating a conventional rapid prototyping apparatus. As shown in FIG. 1A, the conventional rapid prototyping apparatus 1 comprises a powder feeder 10, a construction platform 11, a construction chamber 12, a printing module 13 and a liquid supply module 14. The powder feeder 10 is disposed over the construction platform 11 for accommodating construction powder (not shown) and feeding the construction powder to the construction platform 11. Then, the construction powder on the construction platform 11 is pushed to the construction chamber 12 by a spreading element (not shown), which is linked with the printing module 13. Then, high viscosity liquid binder is printed on the construction powder by the printing module 13. Consequently, the liquid binder and the powder stick together to become solidified. The liquid supply module 14 is in communication with the printing module 13 for supplying the liquid binder. After the above steps are repeatedly done, a three-dimensional physical object is produced in the construction chamber 12 by stacking multiple layers.
Regardless of the size of the three-dimensional physical object or the improvement of the rapid prototyping apparatus, it usually takes several hours or several tens of hours to produce the three-dimensional physical object. Whenever the high viscosity liquid binder is printed on the construction powder, it takes a drying time to wait for the formation of the construction layer. Consequently, the process of stacking the multiple layers is time-consuming. Moreover, after the three-dimensional object is produced, a high temperature heating process is performed to thermally treat the three-dimensional object so as to increase the structural strength of the three-dimensional object. If the structural strength is insufficient, the possibility of causing damage of the three-dimensional object is increased. In other words, the time cost of the rapid prototyping process is very high.
Moreover, the conventional rapid prototyping process is largely affected by the ambient humidity. For example, if the ambient humidity is higher, the moisture of the construction powder is higher. Under this circumstance, the procedure of falling down the construction powder and the procedure of spreading the construction powder are adversely affected, and thus the performance of the three-dimensional object is deteriorated. FIG. 1B is a schematic cross-sectional view illustrating the conventional rapid prototyping apparatus of FIG. 1A. For increasing the drying rate, the conventional rapid prototyping apparatus 1 is usually equipped with a hot air dryer 15. The hot air dryer 15 is disposed over the construction chamber 12. While the rapid prototyping process within the construction chamber 12 is performed, the construction powder is heated by the hot air dryer 15. Consequently, the drying rate is enhanced. Although the construction powder within the construction chamber 12 is quickly dried, there are still some drawbacks. For example, the heat absorbed by the construction powder will be transferred to the inner components of the conventional rapid prototyping apparatus 1 and radiated to the near component (e.g. the printing module 13). Owing to the high ambient temperature of the hot air dryer 15, some nozzles of the printing module 13 are possibly clogged. Consequently, the print pattern printed by the printing module 13 contains thin white lines corresponding to clogged nozzles, and the quality of the three-dimensional object is impaired. Moreover, the use lives of the inner components of the rapid prototyping apparatus 1 and the printing module 13 will be shortened.
For solving the above drawbacks, there is a need of providing a powder heating assembly and a heating module of a rapid prototyping apparatus so as to increase the forming speed and the quality of the three-dimensional object.